Process for bodying vegetable drying



PROCESS FOR BODYING VEGETABLE DRYING OILS WITH POLYMER OIL Donald F. Koenecke, Westfield, N. J., assignor to Esso Research and Engineering Company, a corporation of Delaware N Drawing. Original application July 16, 1949, Serial No. 105,261, now Patent No. 2,709,662, dated May 31, 1955. Divided and this application December 29, 1953, Serial No. 401,085

11 Claims. (Cl. 106-265) This invention relates to an improvement in drying oils and more particularly to an improvement in accelerating the heat bodying rate of vegetable oils without depreciating the drying rate or film forming properties of the product and is a division of application Ser. No. 105,261, filed July 16, 1949, now Patent No. 2,709,662, issued May 31, 1955.

When vegetable oils such as linseed oil are cooked to increase the viscosity in customary manner, a reaction time of about 12 hours is required to effect the change. The temperatures necessary for this purpose are in the range of 295 to 305 C., and the conventional heating procedure is therefore usually accompanied by an undesirable darkening of the treated oil as well as an appreciable loss of material due to the extended cooking. Attempts have been made in the past to increase the low rate of production and to reduce the concomitant degradation of the oil. These previous attempts have been centered on the use of reactive monomers such as styrene, butadiene, cyclopentadiene, or of catalysts such as oxygen or litharge, but in varying degrees the use of any of these materials meant a high loss or an impairment of drying rate, color or some other property of the eventual product. Thu-s the improvement in cooking rate was obtained only at a serious sacrifice which could not always be afforded depending on the vegetable oil used and the ultimate use contemplated therefor.

It has now been discovered that certain synthetic oily polymers of diolefins have a surprisingly beneficial accelerating effect on the cooking rate of vegetable drying oils without causing loss of color and often actually causing an improvement in hardness and other properties.

Vegetable drying or semi-drying oils to. which the present invention is applicable include linseed oil, soybean oil, rapeseed oil, tung oil, cottonseed, perilla, oiticica, corn, dehydrated castor, fish-oil, sunflower seed, safllower and other vegetable oils containing a substantial proportion of glycerides of linoleic and/ or linolenic acid.

The synthetic oils useful for catalyzing the cooking reaction in accordance with the 'presentinvention are oily polymers of butadiene isoprene,.dimethyl butadlene,

piperylene, methyl pentadiene or other conjugated diolefins having four to six carbon atoms per molecule. Instead of polymerizing any of the. aforesaid. diolefins alone, they may be copolymerized in admixtures with each other or in admixtures with minor amounts of ethylenically unsaturated monomers copolymerizable therewith, e. g., with to 30% of styrene, styrenes having alkyl groups substituted on the ring such as para methyl styrene, dimethyl styrene or diethyl styrene, acrylonitrile, methacrylonitrile, methyl acrylate, methyl methacrylate, vinyl isobutyl ether, methyl vinyl ketone, and isopropenyl methyl ketone. Such synthetic oils may be advantageously prepared by mass polymerization either in the presence of a hydrocarbon soluble peroxide catalyst such as benzoyl peroxide or cumene hydroperoxide, or in the presence of metallic sodium when the monomers consist of a diolefin or of a mixture of a diolefin with a v 2,846,329 Patented A .5;

"ice

2 styrene compound. Suitable polymerization procedures are illustrated below in runs A and B. Throughout the present description it will be understood that all proportions are expressed on a weight basis unless otherwise specified.

Run A.-Forexample, 100 parts of butadiene-1,3, 50 parts of straight run mineral spirits boiling between 150 and 200 C. (Varsol), 3 parts of t-butyl hydroperoxide (60% pure) and 0.75 part of diisopropyl xainthogendisulfide are heated in a closed reactor at about 90 C. for 40 hours, whereupon the residual'pressure is released and unreacted. butadiene isallowed' tovolatilize from the polymerized-mixture at 70 C." 'The'resultingproduct', which is a clear, water-white solution, consists typically of about 60 parts of oily polymer'of butadiene, about 4 parts of butadiene dimer, plus solvent and some t-butyl alcohol. This solution of polymer is then preferably fractionated to remove the dimer and usually adjusted to 50% non volatile matter content. The non-volatile constituent, which isthe oily polymer of butadiene, has a molecular weight between 1,000 and 10,000, preferably between 2,000. and 5,000. It will be understood, of course, that the foregoing, procedure is 5 only. illustrative and that it; can be modified in many ways, particularly as described in U; S..Patentl Application Serial No. 782,850 of Arundale et' al., filed on October 29, 1947,;now Patent No. 2,586,594, issued February 19, 1952, which describes alternative monomers, catalysts, reaction diluents, polymerization modifiers, suitable ranges of proportions of the various ingredients, suitable ranges of'polymeriz' ation conditions, etc. 7 v

Run B.An' alternative polymerization method'using sodium as catalyst is illustrated as follows: parts of butadiene-l'fi, 20 parts of styrene, 200 parts of straight run mineral spirits boilingibetween 150 and 200 C., 40 parts of dioxane, 0.2 part of isopropanol and 1.5 parts of finely; dispersed sodium are heated at about 50 C. in a closed reactor provided with an agitator. Complete conversion is obtained in about 4.5 hours whereupon the catalyst is destroyed by adding an excess of isopropanol to the polymerized charge. The crude product is cooled, neutralized with carbon dioxide or glacial acetic acid or the like and filtered. The colorless filtrate is then fractionally distilled to remove the alcoholand modifiers such as dioxane. Finally, additional hydrocarbon solvent is preferably distilled off until a product. containing about 50%-95% non-volatile matter is obtained, the nonvolatile matter being a drying oil having a molecular weight below 10,000, preferably between about 2,000'to 5,000. i

Again it will beunderstood'that the described sodium polymerization method'ma'ybe varied considerably 'as by omitting the styrene co-reactant; or by adding the styrene only after the polymerization of butadiene monomer had begun; or dioxane may be replaced by 10-to35 partsof another ether-modifier having more than 2 carbon atoms such as methyl ethyl. ether, or the modifier may be omitted altogether, especially when it is not essential to obtain a perfectly colorless product. Similarly, isopropanel is not necessary, though aliphatic alcohols of'less than 6 carbon atoms generally have the beneficial 'efiect of promotingthe reaction when present in amounts ranging. from about 2 to 50% based on the weight of' sodium catalyst. Furthermore, the mineral spirits may be replaced by other inert hydrocarbon diluents boiling between about l5 C. and 200 C.,.e. g,, butane, benzene, xylene, cy-clohexane and the like. The diluents are usually used in amounts ranging from 50 to 500 parts per 100 parts of monomer. The reaction temperature .may vary between about 40 C. and 100 C., preferably around 65' to C. As a catalyst, 0.1 to 10' parts of dispersed metallic sodium'is used'per'100parts"ofmonomers, sodi= um particle sizes below 100 microns being particularly effective.

In general the synthetic drying oils useful for catalyzing the cooking rate of vegetable oils in accordance with thegpresent invention can becharacterized as being stable upto a temperature of about 305 C. The following examples will serve to illustrate the mode of operation as well as the advantages of the present invention, though it will be understood that various other embodiments or modifications not specificallyillustrated herein are possible without departing from thespirit or scope of the invention. For instance, instead of co-reacting the vegetable drying oil with the synthetic drying oil in a non-catalytic thermal process, the heat bodying reaction may be further accelerated by operating in the presence of a suitable catalyst, e. g., fullers earth or other active clays.

EXAMPLE 1 A mixture of 167.2 parts of alkali refined linseed oil and 35.0 parts of a synthetic oil having a viscosity of 9 poises and containing 50% of oily polybutadiene in straight run mineral spirits, which oil was prepared in accordance with the procedure described in run A above, was gradually heated in one hour from room temperature to .288? C(in a stainless steel kettle, i. e., in an open vessel, held between 288 and 290 C. for 2% additional hours under a blanket of carbon dioxide and then allowed to cool. The resulting oil had the following characteristics: 7

Gardner color; m n.

Gardner viscosity Zg-Zq, (54 poises). Cur'e'point 117 seconds.

1 Gel time of a thin film on a 200' C. hot plate.

A 50% solution of this heat bodied oil of the inventionwas prepared by mixing it with an equal amount of straight run mineral spirits boiling between 150 and 200 C. (Varsol No. 2), and its air drying rate was compared with a solution prepared by mixing the same solvent with an equal amount of a commercial bodied linseed .oilcontaining about 10% of tung oil. The commercial oil had the following characteristics:

Gardner color 7 Gardnerviscosity Z; (36.2 poises). Cure point 152 seconds.

,In evaluatingthe drying rates of the two oil solutions, 0.5% lead and 0.05 manganese in the form of naphth'enatesv were added thereto and the solutions were then poured on tin plate panels. The results obtained are indicated below, the drying rate being measured on an arbitrary scale where represents a completely tackfree film, 6 represents a film set to touch and 3 represents a film which is dust-free.

Sample 1 Br. 2 Hrs. 4 Hrs. 7

Invention---. Commercial Oil 3 Code: 0-Unafiected; 9-Failure.

All evaluations of film resistance described in this specification have been determined as follows:

Water resistance-A piece of filtered paper was placed on top of the tested film and a small amount of water dropped on the paper. The wet paper was left in contact with the film for 5 hours.

Soap resistance-A drop of 2% solution of commercial sodium soap was formed on a filter paper lying on top of the tested film and the wet paper left in contact with the film for 2 hours.

Grease resistance.-A piece of filter paper saturated with a 50-50 mixture of butter and oleic acid was left in contact with the film for 2 hours. 7

Caustic resistanca-A piece of filter paper on which a drop of a 1% aqueous solution of NaOH had been dropped was left in contact with the tested film for one hour.

EXAMPLE 2 Rim I.600 parts of alkali-refined linseed oil were gradually heated to 295 C. over a period of one hour, held at that temperature for two hours under a blanket of carbon dioxide while stirring and finally cooled slowly to room temperature.

Run lI.54O parts of alkali-refined linseed oil were blended with a solution containing 60 parts of the polybutadiene oil described in Example 1 and 74 parts of a straight run mineral spirits boiling between and 200 0., and the blend was heated at 295 C. on the same heat cycle as described in run I above. The mineral spirits were boiled ofi.

Run III.A mixture having the same composition as in run H was gradually heated to 260 C. over a period for about 45 minutes and held at that temperature for 2 hours.-

' An evaluation of the three oils cooked as just described is given in Table II:

Table II Percent Gardner Viscos- Cooking Sample Gardner Visoosity Loss of 7 Color ity (Poise) Oil Polymer 3 Run I 295 o.) 7 M-N 3.30 3. 5 Run II (295 0.) 7 S 6 00 2.0 Run ID. (260 0.) 6-7 F-G 0.5

1 Prior art. 1 Invention.

3 Exclusive otthe mineral spirits solvent.

Comparison of runs I and II shows that the addition of synthetic drying oil causes the natural oil to body more intensively than when no synthetic oil is present during the heating under the same conditions, and the cooking loss is reduced by almost onehalf when the synthetic oil is present. Furthermore, the viscosity data indicate that the same degree of bodying as was obtained in run I can be obtained at substantially lower temperatures when the synthetic-oil is present, and by this expedient the cooking loss can be reduced still further as illustrated by run III. An interpolation of the tabulated data indicates that a bodied oil as viscous and also otherwise at least as good as the product. obtained in-one hour at 295 C. by the .5 prior art method can be obtained in accordance with the invention in the same length of timeat-a temperature of about 275 C., resulting not only in a considerable saving in thermal energy but also in a very important reduction .a saving in heat and a reduction of oil lostjbut'furthermore the product obtained is of noticeably. lighter .color than the oil-bodied to the sameconsistency by the prior .art process. Both oils had the same air drying rates, .being of the cooking loss down to about 1% of the 'drying oil only slightlytacky after 4 hours and virtually tack-"free charged. Alternatively, instead ofreducing the cooking after 24 hours in the presence of 0.5% lead and 0.5% temperature, the addition of the synthetic oil allows the manganese naphthenate drier. cooking step to be carried out in a shorter time span at The properties of films cast from the above oils on tin the same temperature than is possible in the absence of'the plate panels were as follows: synthetic oil. At the same. time the possibility of operating atlower temperatures or for "shorter times is responsible foran improvement in color. All of the foregoing is Air Dried 48 hours) Baked 1 hr.@120 o.) characteristic of the unexpected advantages of the novel cooking process. That the latter does not impair the t I Sample "Resistance to- Resistance to properties of the vegetable oil or of the dried films '15 prepared therefrom but actually improves the hardness Water Soap Grease NaOH Water Soap, Grease NaOH and occasionally also other properties of the films is shown 1 w by the following data obtained on films cast on tin plate Run III... 0 .s 3 '7 0 5 9. 9 panels in the presence of 0.5% lead and 0.05% manganese WW 4 0 0 o 2 naphthenate drier.

171.8 Resistance Again itfis seen that the air dried fihns from .the oil Sample S 1:31;? treated 1n accordance with this invention are approximate- Hess Bend) H201 Soapl Grease] Cam ly equal to the conventionally treated'oll except for a t e 25 slightly lnferior resistance to water. On'the other hand the baked film'frorn the oil treated according to the ini n'e vention was decidedly superior to theprior art oil in 1 I 4 0 9 5 9 terms ofresistance to soap,.grease and alkali. Otherwise g g 2 g g g there was no difierence in physical properties, all of the r tested films being completely tack-free and perfectly 7 0 flexible as determined by bending the coated steel panels 12 0 0 4 4 8 through a 180 degree angle. Bothair dried films were 14 0 slightly soft after 48 hours, but both baked films were 1 Code: OUnafieeted or excellent; 9Fai1ure. E 4

EXAMPLE 3 Th l i l' M t l e present invention is a so app ica e o o eoresmous In thls example a polybutadlene O11 prepared m the varnishes. This is illustrated -by the following runs V presence of sodium catalyst was used to accelerate the heat and VI wherein the reactants indicated in the subjoined bodying of a vfigstable drying The Synthetic on used 40 formulas were heated in l-gal stainless steel kettles to was prepared substantially as described in run B given C on the Same time temperature curve under a earlier herein,except that styrene was omitted from the carbon dioxide blanket with frequent Stirring After polymerization mixture and instead a solution of a butathe temperature of C was reached each varnish diene homopolymer in mineral spirits was prepared and was held at that temperam're unti1.the i time of a after the usual finishing steps reduced by distillation to thin film on a 0 hot plate was brought down to ag 22 2 5;?ai igsgg gi' Sam 16s wereheamd '40-'45 seconds. Thereafter each kettle was quenched to C 1 d held at that temperaturg for threehours in water and the oleoresinous varni'shwa's dilutedwith an equal weight of straight run'mineral 'spirits'boiling on the same heat cycle. In run III representing the prior between 150mm (varsol #2) 7 art, 300 g. of alkali-refined linseed oil were heated in the absence of any added materials whereas in run IV illustrating the invention 30 g. of the polybutadiene 'oil dis- Formulas solved in an equal amount of mineral spirits were addedto RUN V 300 g.'of the same linseed oil. The color and viscosity of g each batch were determined-during the cooking step at 5 gum (pentalyn onehourintervals and the following results were obtained: :824-g"a1ka1i-refin ed linsfwd Oil I Ch t 1 125 g. polybutadiene Qll (prepared by themethod vdeanges m coo mg S ep scribed in run A; added to the linseed oil and ester GARDNER COLOR gum mix as a solution containing 31 g. of straight run 0 mineral spirits) V Sample Initial 3Hrsf 0 Aboutf10 weight. percent. based on the resin andlinseed 4 1 Run III e 7 7-8 8-9 Run 1v e 7 8-9 '89 RUN-v.

427 g. estergum-(pentalyn iA) VISCOSITY (BOISE) 824 g. alkali-refined linseed oil 1 %i915::::::::::::::::::::::: 352 iii if? 33 Cooking observations It will be noticed from the above that the heat bodying Run V Run VI in run IV, which illustrates the invention, occurs at a very much faster rate-than in run III and 'byinterp'olation it 8 t q 5102 can be seen that-the viscosity stage reached inrunIVafter j .5 about '70 minutes is equivalentto the. stage reached in run 0010f, Gardnehfl 2 7 III after three hours. This necessarily results not only in by about 40% in accordance with the present invention.

'As a consequence of this reduced. cooking time the cook loss is also reduced appreciably and a cooked varnish of RUN VIII 650 g. hydrocarbon resin v 910 g. alkali-refined linseed oil 90 g. polybutadiene oil. (prepared by method described 5 in run A; added to linseed oil and resin mix as a solugiiggg i gg ggsi of lead and weight p tion containing 90 g. of straight run mineral spirits) cent of manganese in the form of naphthenates were weight Percent based on linseed added to each of the cookedvarnishes and the latter In each run all the reactants specified above were applied to tin plate panels; films having the following 10 placed in a l-gallon stainless steel kettle, heated to properties were obtained: 295 C. under a carbon dioxide blanket with frequent Resistance to Water Soap Grease NaOH Hard- Tack Flexibility ness (180 Bend) Air Dried Films (48 Hours):

RunV 0 4 0 4 Good. None- Boga crack- Run v1 o 4 o a .-do do. Iii). Baked Films (1 Hr.

RunV 0 0 0 3 d0. .do Unafieoted. Run VI 0 0 0 0 .do do Do.

(lode: 0 Unafiected; 34Appreciable softening; 9-Failure.

It will be noticed that the films resulting from the varnish stirring and maintained at that temperature until the processed according to this invention were substantially cure time of a thin film of the varnish base on a 200 C. equivalent to the prior art product in all properties tested. .hot plate was reduced to 55 seconds. Thereafter the The accelerated varnishes of this invention can also kettle was quenched in water and the varnish base mixed be used'successfully in the preparation of enamels. For t with an equal weight of straight run mineralspirits. example a white enamel was prepared from the varnish obtained in run V by mixing to a smooth paste 245 g. Results of titanium dioxide pigment and 2.00 g. ofthe varnish and grinding the paste to enamel particle size on a Run VII Run Vm pigment roller mill. The resulting paste was mixed further with an additional "400 g. of the same varnish, Cooktimehoms 4:08 3:12 15 g. of 10% lead and 1% of manganese drier (the viswsitymoifie Gel drier being a solution of metal naphthenates in xylol) and of 2% cobalt naphthenam In a contiol It will be noticed that in accelerated run VIII the varnish run the saime procedure was w u.smg i varnish was cooked much too far although the cooking time g g sf g i g g l :33 igg gg i g thereof was almost a whole hour shorter than inunfilms W21 hard and glos s y. IE oi dei to compare theii agcelerateii run The formation f a as i i weathering characteristics, two coats of each enamel were to a varnish bodied Gilly to a vlsqmty of pmse m Sprayed on primed bonderized steel panels which were a substantially longer tmre, clearly illustrates the potency then exposed to the conditions of an Atlas of synthetlc butadiene 011s as accelerators for the heat Meter for 600 hours, said to be the equivalent of 600 bofiiymg or Polymerization of vegetable oils and of days of exterior exposure. Both white enamels behaved resmous vamlshesthe same way in that they lost gloss to an eggshell appearance and displayed some microcracking at the end 7 EXAMPLE 6 of this rather severe test PCIIOd, showing that the accel- In this example the accelerating efle t of a di f g g treatmeflt i f has styrene copolymer oil was tested in connection with an g g f f i g liggg i f f g 225532 22; oleoresinous varnish containing alkali-refined soybean oil taining toluidine red pigment, both the accelerated and s a g g g gi g the g the unaccelerated enamel showing equal fading after 600 M on 2 par u a i parts 0 xy ene exposure in the weathepGMeter. at-lS with aluminum chloride catalyst.

EXAMPLE 5 Formul s In this example the accelerating eifect of a polybuta-. RUN IX 'diene oil was testedin connection with an oleoresinous 5 hydrocmrbon resin varnish base containing a synthetlc all-hydrocarbon resln 232 g. alkah refined soybean oil prepared by copolymerization of 55 parts butadlene and 45 parts of diisobutylene at 15j C. with aluminum RUN x chloride catalyst, as described in U; S. patent applications Serial No. 610,212, filedAugust 10, 1945, now Patent hYdIPCaYbm mm No. 2,476,000, issued July 12, 1949, and Serial No. 232 a1ka11'T?find SOY'beaHPII 638,514, filed December 29, 1945, now Patent No. butadwne-styrene 0111 (p p as descnbed :1 2,546,020, issued March 20, 1951, ,7 Run B; added to soybean oil and resin mix as a solution Formulas containing 2 g. of straight run mineral spirits) RUN VII 1 10 weight percent based on soybean oil and resin.

650 g. hydrocarbonresin The specified reactants were heated in an aluminum 910 g. alkali-refined linseed oil 7 kettle under a nitrogen blanket with stirring to 295 C.

and held at thattemperature until the "cure-time of a thin film of the varnish base on a 200 Cwhot plate was reduced to 60 seconds. Thereafterthe 'varnishbase was cooled quickly to 230 C. and mixed withan equal weight of straight run mineral spirits.

Results Run 1x *Run x Cook time, hrs 11. 42 5. 52 Cook loss, wt. percent 16. 11.0 Viscosity, poise 4. 0 2. 4 Color, Gardner 14 12-13 It will be noticed again that the cooking time required for the accelerated varnish is only about onehalf that required to polymerize the control varnish to a state characterized by a comparable cure time. Furthermore, in consequence of the reduced cooking time the amount of valuable oil lost during the cooking can be seen to have been reduced by about one-third. The color of the cooked accelerated varnish was again lighter than the non-accelerated varnish.

To show that the cooked accelerated varnish has approximately the same cure time or drying rate as the more viscous product obtained by cooking of the non-accelerated varnish, the products of runs IX and X were mixed with 0.5% lead and 0.05% manganese naphthenate drier, and coated on tin plate panels and tested.

Air drying rate Hours Sample 7 1 RunX 6 2 Rating: 9wet; 6-set-to-touch; 3-dust-free; 0-tack-iree.

The properties of air dried and baked films prepared from each of the varnishes were also compared:

AIR DRIED, 1 WEEK Rating: OUnafiected; l3-Discolored; 4-6-Softened and less adherent; 78-Pin.holed or blistered; 9-Film removed.

Again it can be seen that the two varnishes have approximately equal properties, air-dried films of the accelerated varnish having somewhat superior water and soap resistance than air-dried films of the ordinary varnish whereas in the baked state films of the ordinary varnish show somewhat better resistance to alkali than the corresponding film obtained from the accelerated varnish.

In summary, the invention illustrated by the foregoing examples consists of accelerating the cooking rate of drying or semi-drying vegetable oils by adding thereto about 2 to 25%, preferably about to 15% of an oily butadiene polymer or copolymer and thereafter cooking the mixture is substantial absence of oxygen at a temperature of about 230 to 330 0., preferably 265 C. to 300 C. until the cooked oil has reached the desired consistency or cure time. Instead of applying the invention to the cooking of vegetable oils alone, it can be applied'with equal benefit'to the cooking of oleore'sinous varnishes containing a vegetable oil and about'10'to 70% ofares in such 'as ester gum, various oil soluble hydro carbon resins, phenolics, modified phenolics, maleictreated rosins and esters, 'and natural resins. The principal advantage of the invention lies in the fact that .heat bodying of vegetable oils, which is essentially a polymerization phenomenon, can be accomplished in a shorter time or at a lower temperature or both, and consequently the cook loss as well as the darkening of the valuable charge is kept to a minimum. It follows from the foregoing that the invention offers important economies in heat, time and material, without in any way impairing the properties of the eventual product.

In the course of investigating the present invention, it was established that a substantial preponderance of the vegetable oil over the synthetic butadiene oil is desirable as far as cooking rate is concerned. At the same time, however, the discovery was made that if the proportion is reversed, as by co-reacting about 70 parts of oily butadiene polymer with 30 parts of dehydrated castor oil at 295 C. for eighty minutes, varnishes derived from the resulting base have been found to have an excellent ability to wet metallic and glass surfaces. This is quite surprising in view of the fact that, in the absence of vegetable oil, the drying oils synthesized from butadiene have a tendency to creep and crawl into ri'vulets, leaving a discontinuous film when applied to metal or glass.

I claim:

1. A process for producing a drying oil composition which comprises mixing a copolymer consisting essentially of a non-volatile oily copolymer prepared by copolymerizing a C to C conjugated diolefin with 5 to 30 wt. percent of a styrene in the presence of 50 to 500 parts by weight of a hydrocarbon diluent boiling at 15 to 200 C., 10 to 35 parts by weight of an ether having more than 2 carbon atoms, and 0.1 to 10 parts by weight of finely divided sodium metal catalyst, said copolymer having a molecular weight of from 1,000 to 10,000 and being stable up to about 305 C., with a vegetable oil chosen from the group consisting of drying and semi-drying oils, said copolymer being present in an amount of from 2 to 25% by weight of said vegetable oil, and heating the resulting mixture at a temperature of about 230-330 C. until the vegetable oil has reached the desired consistency.

2. Process according to claim 1 in which the diolefin is butadiene-1,3.

3. Process according to claim 2 in which the copolymer is composed of 60 to 90% of combined butadiene and 40 to 10% of combined styrene.

4. Process according to claim 3 in which the copolymer oil is prepared by copolymerizing butadiene and 20% styrene.

5. A drying oil composition of improved drying characteristics which comprises a thermally treated mixture, said mixture consisting essentially of a nonvolatile oily, copolymer prepared by copolymerizing a conjugated C to C diolefin with 5 to 30 wt. percent of a styrene in the presence of 50 to 500 parts by weight of a hydrocarbon diluent boiling at 15 to 200 C., 10 to 35 parts by weight of an ether having more than 2 carbon atoms, and 0.1 to 10 parts by weight of finely divided sodium metal catalyst, said copolymer having a molecular Weight of from 1,000 to 10,000 and being stable up to about 305 C., with a vegetable oil chosen from the group consisting of drying and semi-drying oils, said copolymer being present in an amount of from 2 to 25% by weight of said vegetable oil,

8. Process according to claim 3 inwhich the vegetable oil islinsced oil. s h

9 Process according to claim 3 in which the vegetable oil is soybean oil.

l0. Composition according to claim 6 in which the vegetable oil is linseed oil. I

11. Composition according to claim 6 in which the vegetable oil is soybean oil. 2 i 2 ReferencesCitcd in the file of this patent TED :STATES PATENTS Lycan et a1 Junc8, '1948 Gleason Jan. 2, 1951 Crouch Sept. 25, 1951 Hyllyer Jan. 8, 1952 Marhofer et a1 Sept. 29, 1953 Koenccke et al May 31, 1955 

1. A PROCESS FOR PRODUCING A DRYING OIL COMPOSITION WHICH COMPRISES MIXING A COPOLYMER PREPARED BY COPOLYMEROF A NON-VOLTAILE OILY COPOLYMER PREPARED BY COPOLYMERIZING A C4 TO C6 CONJUGATED DIOLEFIN WITH 5 TO 30 WT. PERCENT OF STYRENE IN THE PRESENCE OF 50 TO 500 PARTS BY WEIGHT OF HYDROCARBON DILUENT BOILING AT -15 TO 200*C., 10 TO 35 PARTS BY WEIGHT OF AN ETHER HAVING MORE THAN 2 CARBON ATOMS, AND 0.1 TO 10 PARTS BY WEIGHT OF FINELY DIVIDED SODIUM METAL CATALYST, SAID COPOLYMER HAVING A DIVIDED SODIUM METAL CATALYST, SAID COPOLYMER HAVING A UP TO ABOUT 305*C., WITH A VEGETABLE OIL CHOSEN FROM THE GROUP CONSISTING OF DRYING AND SEMI-DRYING OILS, SAID COPOLUMER BEING PRESENT IN AN AMOUNT OF FROM 2 TO 25% BY WEIGHT OF SAID VEGETABLE OIL, AND HEATING THE RESULTING MIXTURE AT A TEMPERTURE OF ABOUT 230-330*C. UNTIL THE VEGETABLE OIL HAS REACHED THE DESIRED CONSISTENCY. 